87 lines
2.8 KiB
C
87 lines
2.8 KiB
C
/***********************************************************************/
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/* */
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/* Objective Caml */
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/* */
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/* Xavier Leroy, projet Cristal, INRIA Rocquencourt */
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/* */
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/* Copyright 1996 Institut National de Recherche en Informatique et */
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/* en Automatique. All rights reserved. This file is distributed */
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/* under the terms of the GNU Library General Public License, with */
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/* the special exception on linking described in file ../../LICENSE. */
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/* */
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/***********************************************************************/
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/* $Id$ */
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#include <errno.h>
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#include <string.h>
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#include <mlvalues.h>
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#include <memory.h>
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#include <signals.h>
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#include "unixsupport.h"
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#ifndef EAGAIN
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#define EAGAIN (-1)
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#endif
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#ifndef EWOULDBLOCK
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#define EWOULDBLOCK (-1)
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#endif
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CAMLprim value unix_write(value fd, value buf, value vofs, value vlen)
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{
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long ofs, len, written;
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int numbytes, ret;
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char iobuf[UNIX_BUFFER_SIZE];
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Begin_root (buf);
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ofs = Long_val(vofs);
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len = Long_val(vlen);
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written = 0;
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while (len > 0) {
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numbytes = len > UNIX_BUFFER_SIZE ? UNIX_BUFFER_SIZE : len;
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memmove (iobuf, &Byte(buf, ofs), numbytes);
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enter_blocking_section();
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ret = write(Int_val(fd), iobuf, numbytes);
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leave_blocking_section();
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if (ret == -1) {
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if ((errno == EAGAIN || errno == EWOULDBLOCK) && written > 0) break;
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uerror("write", Nothing);
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}
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written += ret;
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ofs += ret;
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len -= ret;
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}
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End_roots();
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return Val_long(written);
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}
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/* When an error occurs after the first loop, unix_write reports the
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error and discards the number of already written characters.
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In this case, it would be better to discard the error and return the
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number of bytes written, since most likely, unix_write will be call again,
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and the error will be reproduced and this time will be reported.
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This problem is avoided in unix_single_write, which is faithful to the
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Unix system call. */
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CAMLprim value unix_single_write(value fd, value buf, value vofs, value vlen)
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{
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long ofs, len;
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int numbytes, ret;
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char iobuf[UNIX_BUFFER_SIZE];
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Begin_root (buf);
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ofs = Long_val(vofs);
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len = Long_val(vlen);
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ret = 0;
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if (len > 0) {
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numbytes = len > UNIX_BUFFER_SIZE ? UNIX_BUFFER_SIZE : len;
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memmove (iobuf, &Byte(buf, ofs), numbytes);
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enter_blocking_section();
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ret = write(Int_val(fd), iobuf, numbytes);
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leave_blocking_section();
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if (ret == -1) uerror("single_write", Nothing);
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}
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End_roots();
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return Val_int(ret);
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}
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